Characterization of DNA release from composites of oligo(poly(ethylene glycol) fumarate) and cationized gelatin microspheres in vitro

Abstract

This research investigates the release of plasmid DNA from novel hydrogel composites of oligo(poly(ethylene glycol) fumarate) (OPF) and cationized gelatin microspheres (CGMS), as well as the swelling and degradation of these materials in vitro. The release of total DNA and of double-stranded DNA was measured fluorescently, and the swelling properties and polymer mass loss of the hydrogels were assessed. Further, the structural integrity of the released DNA was determined through electrophoresis. It was found that plasmid DNA can be released in a sustained fashion over the course of up to 49-140 days in vitro from hydrogels of OPF synthesized from poly(ethylene glycol) of nominal molecular weights of 10 kDa and 3 kDa, respectively, with the release kinetics depending upon the material composition and the method of DNA loading. Released DNA was predominately double-stranded DNA (dsDNA) in structure and of the open-circular conformation. The results suggest that DNA release from hydrogel composites of OPF and CGMS is dominated by the degradation of the OPF component of the gels. Electrophoresis results indicate that the released DNA retains suitable conformation for potential bioactivity over the course of at least 63 days of release. Thus, these studies demonstrate the potential of composites of OPF and CGMS in controlled gene delivery applications.

Peripheral Nerve Grafts and Chondroitinase ABC Application Improves Functional Recovery After Complete Spinal Cord Transection

“…Previous researchers have shown that drugs can be released from oligo-(polyethylene glycol) fumarate (OPF) hydrogel for a sustained time period [25,26]. The release profile can be tailored by changing the molecular weight of the polyethylene glycol, which changes the amount of crosslinking in the hydrogel [27].…”

Sustained Delivery of Dibutyryl Cyclic Adenosine Monophosphate to the Transected Spinal Cord Via Oligo [(Polyethylene Glycol) Fumarate] Hydrogels

“…23,24 Potential applications of these hydrogels include bone tissue engineering, [24][25][26][27] scaffold material for marrow stromal cell attachment and differentiation, [28][29][30][31] cell encapsulation, 30,31 cartilage tissue engineering, 32 and the controlled release of various compounds. [33][34][35] Recent studies suggest applications in the nervous system using positively charged hydrogels. 36 These researchers demonstrate the capability of OPF hydrogels for sustaining growth of both primary nerve cells and neural support cells that are critical for regeneration.…”

“…40,44 Novel approaches to PLGA microsphere incorporation into three-dimensional biodegradable scaffolds include fusion of protein loaded spheres into scaffolds using dichloromethane vapor. 45 While incorporation of PLGA microspheres into threedimensional OPF scaffolds has not yet been demonstrated, release of DNA 33,34,46 and growth factors 35 from gelatin microspheres within OPF hydrogels has been shown. To assess the feasibility of incorporating OPF hydrogel and PLGA microsphere technology, we sought to release dibutyryl cyclic adenosine monophosphate (dbcAMP) to the transected spinal cord.…”

Delivery of Plasmid DNA Encoding Bone Morphogenetic Protein-2 with a Biodegradable Branched Polycationic Polymer in a Critical-Size Rat Cranial Defect Model

“…Acidic GMPs, which are negatively charged at physiological pH, were loaded electrostatically with net positively charged TAPP/ pDNA polyplexes. These enzymatically degradable GMPs have been used previously to deliver both growth factors 9,10,12 and pDNA [13][14][15] in a sustained manner. The overall objective of this study was to evaluate the ability of composite scaffolds comprising pDNA complexed with a TAPP, GMPs, and a porous PPF scaffold to control the release of pDNA and induce bone formation in a critical-size rat cranial defect.…”